Widely prevalent as a conventional printer is one that prints an image by forming an electrostatic latent image on the surface of a photosensitive drum by selectively irradiating it with light from a print head having multiple light emitting elements such as LEDs (Light Emitting Diodes) and light emitting thyristers disposed in alignment in an exposure device and developing a toner image by having a toner adhere to this electrostatic latent image. In the exposure device among them, multiple light emitting element chips or the like provided with multiple light emitting elements and multiple drive circuits that each drive the individual light emitting elements are attached in alignment along the main scanning direction on a prescribed circuit board.
Formed on the surface of the light emitting element chip is a terminal pad that is electrically connected to the above-mentioned light emitting elements and drive circuits. This light emitting element chip has this terminal pad and a terminal pad installed on the surface of the circuit board electrically connected through wire bonding or the like, thereby receiving a drive current, control signals, etc. from the circuit board to have the individual light emitting elements emit light.
As such a light emitting element chip, there is one that disposes an anode electrode and a gate electrode sandwiching a light emitting thyrister along the sub scanning direction perpendicular to the main scanning direction (see Patent Document 1 for example).